What type of battery? lead acid or AGM, how to replace

[DreamweaverDave]

Thanks to all who post here, I've learned how to change oil to changing front brakes. At first I was hesitant to even touch my wife's 2009 BMW 128i but after reading this I felt better.

Now, I've been reading about AGM batteries and I thought those were in all BMW but when I contacted the dealer he thinks my car has an lead acid bat. He also said a battery replacement will be $425-475 and another $125 to register. He actually stuttered trying to explain.

I can buy one from Auto Zone for $150-175 lead acid or AGM and I've read to attach either a charger or another jumper car to the terminals under the hood. Then remove the battery, but the battery has a big red thing over the positive terminal, how is that removed. I think I've read that there is a switch in the red block?

Also there is a little BMW shop a few miles from the house who will register it for $50

Sorry for the long post.

Thanks
David

[JimD]

The "red thing" is a special terminal BMW uses that cuts power in a crash. It also has fuses in it. It is held in place by the battery, essentially. It removes like a normal battery terminal. You want to be careful that the replacement battery has terminals in about the same location and is pretty close to the same dimensions. It also needs a vent tube in the same location as the stock battery since it's in the trunk (so the vent is more important). But if the battery is functional equivalent, it should go in fine.

Programming (registering) is a little more complicated if you change the battery type. If you put in the same type and size of battery, it is just telling the car it has a new battery. If I remember right, that is in software called "Tool32". If you change the size or type, you also have to go into NCSExpert to tell the car it's a different size and/or type of battery. If you want to change, you might want to be sure that your little BMW shop can also tell the car about the change in battery.

Even $200 for a battery seems steep to me. But bimmer parts are not the cheapest.

[DreamweaverDave]

JimD thanks for the info.

The $150 was for a lead acid and the $175 was for an AGM battery, both from Auto Zone and both prem. bat. with 3 yr replacement warrenty.

I currently have a white battery and it sounds like it is a lead acid.

I will research and find the one that matches the dimensions and vent position etc. I read that some of the quick search things for the auto parts stores do not always show the correct battery.

Thanks again,

DD

[halfhalo]

I replaced my lead acid battery with the autozone AGM one (IIRC the H8 one) and it fits fine. The vent tube plugs in easily, although at my autozone for whatever reason the H8's didn't come with a plug for the second vent hole, while all the other sizes did, so either make sure you find one that has one or just grab it off another size (which I did after I pointed it out to the guy there).


I did the programming/registering myself, so the total cost was 179 minus the core for a new battery.

[trainerjon]

Originally Posted by halfhalo

I replaced my lead acid battery with the autozone AGM one (IIRC the H8 one) and it fits fine. The vent tube plugs in easily, although at my autozone for whatever reason the H8's didn't come with a plug for the second vent hole, while all the other sizes did, so either make sure you find one that has one or just grab it off another size (which I did after I pointed it out to the guy there).


I did the programming/registering myself, so the total cost was 179 minus the core for a new battery.

How did you do the programming/registering yourself? What tools did you use for this?
thanks!

[GuamX1]

Originally Posted by trainerjon

How did you do the programming/registering yourself? What tools did you use for this?
thanks!

I second this

[bmw1racer]

Originally Posted by Guam135i

I second this

Two choices:
1. Bluetooth OBD2 dongle and BMWhat app.
2. OBD2 USB dongle/cable and NCS Expert.

[Iron Man]

Originally Posted by bmw1racer

Two choices:
1. Bluetooth OBD2 dongle and BMWhat app.
2. OBD2 USB dongle/cable and NCS Expert.

For an iPhone, you would need a WiFi adapter, in place of Bluetooth.

[bmw1racer]

Originally Posted by Iron Man

For an iPhone, you would need a WiFi adapter, in place of Bluetooth.

Ah, true... I never think about Apple products.